i wonder why noone made a small tut. that will explane clearly how client server work, i mean something that just show "hello i'm a client #" on the server and viceversa.

actually i'm using the trial, but when i run the engine with the parameter -sv it say "unaviable feature" ... that's 'cause it's a demo ?

yes, you need to read the features difference table, there are many disabled features on the demo, you need at least commercial to make this work.